fix: add binary directory to PATH when ignoring existing binaries

When ignore-existing-binary is true and binary exists, the action would
skip adding the directory to PATH, causing 'command not found' errors
in subsequent workflow steps.

Ticket: DO-14423

Author: therealdwright

dist/index.js

@@ -87,6 +87,8 @@ async function installGitHubReleaseBinary(
   if (fs.existsSync(destinationFilename)) {
     if (ignoreExisting) {
       core.info(`Binary already exists at ${destinationFilename}, ignoring and leaving system as-is`);
+      // Still add the directory to PATH so the binary can be found
+      core.addPath(destinationDirectory);
       return;
     }
   }